Analyser sampling system

Hey guys,
We have an analyser system to measure oxygen, carbon monoxide and carbon dioxide from process gas. We are using Oxymeter 4000. We normally do calibration every week considering the criticality of process. Everytime we have to change the filter used before the analyser. Filter is of 7 micron. Our assumption is that the sampling system is not working properly. Is there a cost effective way to improve the sampling system?